Spring balancer



March 2, 1937. c. N. DOUGLASS I 2,072,582 SPRING BALANCER Fil dJan. 25, 1956 2 Sheets-Sheet 1 m N m m N R Q N2 7 R %N MN m r 1 m a 3G} \NK QN NN QM. mum m B m 2 Sheets- Sheet 2 C. N. DOUGLASS SPRING BALANCER Filed Jan. 23, 1956 March 2, 1937.

, NW 1 m m m MJWWW w w g m w m H- 7 0 v, A W M I C I w mw H w m v E P Q B h 9 Q N n 7 1 W q m m w n 5-: r L m F a \wfi E Patented Mar. 2, 1937 NETE A'iENT OFFICE SPRING BALANCER Application January 23, 1936, Serial No. 60,381

11 Claims.

This invention relates to balancers and more particularly to spring balancers for suspending portable power operated tools such as electric drills, reamers, polishers, and the like from overhead supports.

A balancer of the character referred to comprises a drum or reel, a cable windable on the drum and a spiral spring associated with the drum for turning the drum in a direction to wind up the cable to raise the tool or other load attached to the cable. The tension of the spring is adjusted to counterbalance the weight of the load on the cable, whereby the tool may be suspended at the place for use and be conveniently and easily raised, lowered, and handled by the operator without supporting its full weight. The balancer being suspended from an overhead support, enables the tool to be raised to a position out of the way when not in use.

One object of my invention is to provide a safety lock, operable upon the breaking or release of the spring to hold the drum or reel against rotation to prevent dropping of the load supported by the drum.

In carrying out this object, in connection with a single spring balancer, I provide a pivoted lever carried by the drum and having a portion extending into the path of outward expansion of the spring on breaking or releasing to project a locking element into locking engagement with the drum casing to hold the drum against rotation.

A further object of my invention is to provide a balancer construction which enables a single spring balancer to be readily and easily converted into a double spring balancer to increase the capacity of the balancer without changing the drum for the cable or the main frame or cover section for the drum.

The invention consists further in the features hereinafter described and claimed and shown in the accompanying drawings, in which:-

Fig. 1 is a vertical sectional view with parts in elevation of a single spring balancer embodying the safety lock of my invention, said section being 5 taken on line l-l of Fig. 2;

Fig. 2 is a front elevational View of the balancer of Fig. 1;

Fig. 3 is a horizontal sectional View taken on line 3-3 of Fig. 1, the plunger of the safety lock 50 being shown in locking position;

Fig. 4 is a vertical sectional view with parts broken away and in section, respectively, showing the single reel balancer of Fig. 1 converted into a double spring balancer in accordance with my 55 invention;

Fig. 5 is a rear elevational view with parts broken away and in section, respectively, of the balancer of Fig. 4; and

Fig. 6 is a sectional view taken on line 6-6 of Fig. 4. 5

Referring to Figs. 1 and 2, l indicates the balancer drum or reel mounted for rotation on a shaft 2 journalled in a casing 3 which houses the drum. This casing comprises a main or body section 4 fitting about the drum and a remov- 10 able cover section 5 closing the rear side of the section 4. The sections 4 and 5 are secured together by one or more cap screws 6 as shown.

The drum I has a tapered'peripheral portion 1 provided with a spiral groove 8 to receive a cable 9. 15 The cable has its inner end (not shown) secured to the larger end of the drum in the terminal convolution of the spiral groove. The outer end of the cable is exterior of the drum casing, the cable passing out of the casing 3 through a cable 20 outlet opening in in the section 4 as shown in Fig. 2. The outer end of the cable is equipped with a hook or equivalent means whereby a portable tool or other load may be removably attached to the cable. 25

A spiral spring H turns the drum in a direction to wind the cable on the drum. This spring, as shown in Fig. 1, is located within the drum and has its outer end (not shown) anchored to the drum in any preferred manner. The inner end 39 i2 of the spring is anchored to a sleeve I3 keyed to the shaft 2. This anchorage may be accomplished by inserting the inner end of the spring in a slot in the sleeve, the spring winding about the sleeve holding the spring end in the slot. 35

The drum turns with respect to the shaft and the sleeve. The shaft is normally held against rotation by a worm gear assembly at one end of the shaft. This assembly comprises a worm gear M fixed to the shaft and a worm pinion l5 in 40 mesh with the worm gear and journalled in the casing section 4 as indicated in Fig. 1. One end of the pinion I5 is accessible from the exterior of the drum casing for turning to wind up the spring to adjust its tension. The end portions of the shaft 2 are journalled in the casing sections 4 and 5, respectively, and anti-friction bearings mount the drum on the shaft, as shown.

The safety lock of my invention in the particular embodiment shown in Fig. 1 comprises a lever 56 located within the drum I and pivoted by a pin ll between a pair of ears or lugs it) carried by the innermost spring cover plate i9. This plate rotates with the drum and so does the plate 20 which covers the outer side of the spring.

These plates fit within the drum and prevent lateral buckling of the spring. A cover plate 2I is secured to the drum over the spring assembly and accommodates one of the anti-friction bearings as shown.

The outer or free end 22 of the lever I6 is angularly disposed with respect to the lever and extends into the spring chamber between the plates I9 and through a slot 23 in the marginal portion of the plate I9. This locates the angled end 22 of the lever beyond the periphery of the spring II and in the path of outward expansion of the spring on breaking or releasing to force the lever outwardly from the plate I9.

A plunger 24 is slidably mounted in the end wall 25 of the drum I opposite the lever I6. The inner end of the plunger is slotted, as at 26, to receive the lever and interconnect the parts. A coiled spring 21 fits about the plunger and normally holds the plunger and the lever in the positions shown in Fig. 1 to function on the breaking or release of the drum spring II. The outer end of the spring 21 seats against the drum wall 25, while the inner end of said spring bears against the lever I6 and a shoulder provided by a head 28 at the inner end of the plunger. The plunger carries a coiled spring 29 located within the plunger in a recess 39 therein and bearing at its outer end against the plunger at the bottom of said recess and its inner end against the lever I6.

The end wall 32 of the casing section 4 opposite the end wall 25 of the drum is provided with a series of apertures 33 circumferentially arranged about the axis of rotation of the drum. These apertures are disposed to receive the plunger 24 when the plunger is projected outwardly by the lever I6 as shown in Fig. 3. Thus, when the plunger enters an aperture 33, the drum is held from rotation and dropping of the load on the cable 9 is prevented. The lever I6 acts on the plunger through the spring 29, which also cushions the blow should the plunger strike the drum casing between the apertures when forced outwardly by the lever. This cushioning is essential for when the drum spring releases, the blow on the lever is rather violent.

The balancer has a bracket fixture, indicated generally at 34 in Fig. 2 for suspending the balancer from an overhead support. This fixture is attached to the casing section 4 and extends above the same where it is provided with an attaching hook or equivalent means (not shown).

To convert the single spring balancer of Fig. 1 into a double spring balancer to increase its load handling capacity, the shaft 2 and cover plates 5 and 2| are replaced by a shaft 35, cover section 36 and spiral spring assembly 31, as shown in Fig. 4. The cover section 36 is secured to the casing section 4 by the same cap screws 6 as shown. The cover section 36 is shaped to enclose the second spring assembly 31 which comprises a spring housing or barrel 38, spiral spring 39 and hub sleeve 40. The spring housing 38 is secured to the drum I to rotate therewith, any desired form of connection being employed, as for example, capscrews 4| as shown in Fig. 4. These cap screws are also employed to secure the cover 2| to the drum as shown in Fig. l. The outer end of the spring 39 is anchored to the drum housing 38 on a cross pin 42, which arrangement may be employed in the drum I for the spring II. The inner end of the spring 39 is anchored to the sleeve 40 in the same manner as described for the drum I, and both sleeves 59 and I3 are keyed to the shaft The keyed connection is shown in 5 and this connection is also employed in Fig. 1 be tween the shaft 2 and the sleeve I3. Thus, the shafts 2 and 35 may be interchangeably used with the drum I and its sleeve IS. The only difference is that the shaft 35 is longer to support both sleeves and be journalled in the casing sections 4 and 35, respectively. The keyed ccnnec tion slidably connects the shafts with their sleeves, each sleeve being substantially alike and having opposed grooves 33 in its bore to receive portions 44 of the shaft, the latter being made non-circular in shape to fit the grooves as in-- dicated in Fig. 6.

The cable is wound on the drum I as before. Only the spring capacity for the drum is doubled and thus heavier loads may be handled than with the single spring construction. The safety lock for the spring II in the drum I is retained as shown in Fig. 4. A safety lock for the added spring 39 is shown in Fig. 5.

The second safety lock comprises a plunger 45 mounted in the barrel 38 and normally retracted into the barrel by a coiled spring 46 about the plunger as shown. The plunger extends through the barrel 38 and its inward movement is limited by a split locking ring 41. A series of abutments 48 are provided in the cover section 36. These abutments like teeth, are arranged in circumferential spaced relation about the cover section and are disposed to be in the path of the plunger 45 when the latter is projected outwardly from the barrel 38 on the breaking or release of the spring 39. Thus should the second spring break, the drum. I is held from rotation and dropping of the load carried by the cable is prevented.

The double spring balancer may be readily and easily changed back to a single spring one by merely restoring the construction to that shown in Fig. 1. In the safety lock for the drum I, the lever I6 and the plunger 24 are located at the side of the drum spring II adjacent to the end wall 32 of the housing section 4. The plunger 24 operates axially of the drum I to enter the openings 33 in said end wall, and the lever I6 is disposed radially of the drum to co-act with the plunger. Moreover, the pivotal point I! for the lever I6 is between the plunger 25 and the axis of rotation of the drum. In the safety lock for the second spring 39, the plunger 45 acts radially of the barrel 38.

The details of construction and arrangementof parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention, except as pointed out in the appended claims.

I claim as my invention:

1. In a balancer of the character described, a rotatable drum. a cable windah-le on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, 2. plunger and a pivotally mounted lever carried by the drum at one side of said spring, said lever cooperating with the plunger and having an inclined portion to be struck by the drum spring on breaking or releasing to project the plunger into locking engagement with the housing to hold the drum against rotation, and yieldable means for normally holding the plunger out of engagement with the housing and the lever in operative relation to the drum spring.

2. In a balancer of the character described, a

rotatable drum, 2, cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a cover plate for one side of the spring and rotatable with the drum, a spring biased plunger carried by the drum and normally held out of engagement with the housing, and a pivotally mounted lever carried bysaid cover plate and cooperating with the plunger, said lever having an angled end extending over the periphery of the drum spring through a slot in said cover plate to be struck by the drum spring on breaking or releasing to project the plunger into locking engagement with the housing to hold the drum against rotation.

3. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, a plunger and a pivotally mounted lever carried by the drum at one side of said spring, said lever cooperating with the plunger and having an inclined portion extending over the periphery of the spring to be struck thereby on breaking or releasing to project the plunger into locking engagement with the housing to hold the drum against rotation, yieldable means for normally holding the plunger out of engagement with the housing and the lever in operative relation to the drum spring, and spring means for cushioning the action of the lever on the plunger.

4. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to Wind the cable thereon, a housing for the drum, said housing having an end Wall at one side of the spring and provided with a series of openings arranged in concentric relation to the axis of rotation of the drum, a plunger .and a pivotally mounted lever carried by the drum at 1e side of the drum spring adjacent said end wall, said lever cooperating with the plunger and having an inclined portion extending over the periphery of the drum spring and operable thereby on breaking or releasing to project the plunger into an opening in said end wall for holding the drum against rotation, yieldable means for normally holding the plunger out of engagement with said end wall and the lever in operative relation to the drum spring, and spring means for cushioning the action of the lever on the plunger.

5. In a balancer of the character described, a rotatable drum, a cable windable on said drum, a barrel secured to said drum, a pair of spiral springs, one in the drum and the other in the barrel, said springs serving to rotate the drum and the barrel in unison in a direction to wind the cable on the drum, a housing comprising a pair of detachably connected sections, one section enclosing the drum and the other section enclosing the barrel, and a pair of safety locks, one carried by the drum and the other carried by the barrel, each lock having .a plunger projectable into locking engagement with the associated section of the housing on the release or breaking of the associated spring to hold the drum against rotation, the plunger for the drum acting transversely to the drum spring and engageable with the housing section at one side of the drum, the plunger for the barrel acting radially of the barrel spring and engageable with the portion of the housing section encircling the barrel.

6. In a balancer of the character described, a rotatable drum, a cable windable on the drum,

a. spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, a plunger and an operating member therefor both carried by the drum at one side of said spring and arranged with the member extending radially of the drum and the plunger movable axially thereof, said member being operable by the expansive action of the drum spring on breaking or releasing to project the plunger into locking engagement with the housing for holding the drum against rotation, and yieldable means for normally holding the plunger out of locking engagement with the housing and the member in operative relation to the drum spring.

7. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum and having a series of openings at one side of the drum, a plunger and an operating member therefor both carried by the drum at the side of the drum spring adjacent to said openings and arranged with the member extending radially of the drum and the plunger movable axially thereof, said member being operable by the expansive action of the drum spring on breaking or releasin to project the plunger into one of said openings for locking the drum against rotation, and yieldable means for normally holding the plunger free of the openings and said member in operative relation to the drum spring.

8. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, a plunger and an operating member therefor both carried by the drum at one side of said spring and arranged with said member extending radially of the drum and the plunger movable axially thereof, said member having a portion extending over the periphery of the drum. spring to be struck thereby on the breaking or releasing of said spring to project the plunger into locking engagement with the housing for holding the drum against rotation, and yieldable means for normally holding the plunger out of locking engagement with the housing and the member in operative relation to the drum spring.

9. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, a plunger and an operating lever therefor both carried by the drum at one side of said spring and arranged with the lever extending radially of the drum and the plunger movable axially thereof, said lever having a portion to be struck by the drum spring on breaking or releasing to project the plunger into locking engagement with the housing for holding the drum against rotation, and yieldable means for normally holding the plunger out of locking engagement with the housing and the lever in operative relation to the drum spring.

10. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, said housing having an end wall at one side of the drum, a plunger and a pivotally mounted lever both carried by the drum at the side of the drum spring adjacent said end Wall, said lever cooperating with said plunger and having a portion to be struck by the drum spring on the breaking or releasing thereof to project the plunger into locking engagement with said end wall for holding the drum against rotation, and yieldable means for normally holding the plunger out of locking engagement with said end wall and the lever in operative relation to the drum spring, said lever being interposed between the drum spring and the plunger for transmitting the action of the spring on releasing or breaking to the plunger.

11. In a balancer of the character described, a rotatable drum, a cable windable on the drum, a spiral spring for turning the drum in a direction to wind the cable thereon, a housing for the drum, said drum and said housing having opposed wall portions at one side of said spring, a plunger slidably mounted in the wall portion of the drum and movable axially thereof, a lever cooperating with the plunger and pivotally mounted on the drum at a point between the axis of the drum and the plunger, said lever extending to the outer periphery of the spring and having an angled end to be struck by said spring on the breaking or releasing thereof to project the plunger into locking engagement with the end wall of the housing for holding the drum against rotation, and yieldable means cooperating with the plunger and the lever for normally holding the plunger out of locking engagement with the housing and the lever in operative relation to the drum spring.

CECIL N. DOUGLASS. 

